Why it happens
- Attics in North Carolina summers get extremely hot, and that heat radiates into the rooms below.
- Ducts that run through the attic lose cooling before the air reaches the room.
- Many upstairs floors have a single small return, so air cannot circulate.
- One thermostat downstairs means the system shuts off before upstairs is comfortable.
What helps
- Run the fan on On instead of Auto during hot afternoons to mix air.
- Keep upstairs vents fully open and blinds closed on sunny sides.
- Have airflow and static pressure measured to find the real restriction.
- Seal duct leaks, add or enlarge returns, or balance dampers.
- For bonus rooms, consider a mini split.
